*www.rtings.com/tv/reviews/hisense/u6-u6k
*www.rtings.com/tv/reviews/samsung/cu8000#page-top
Both VU and Hisense are better than Samsung hardware wise. But you need to watch some content on TV, like TV shows, sports to really decide which TV offers best picture quality. Vu and Hisense are brighter than Samsung but you need also compare how is content smoothing. You really need to watch personally in showrooms to decide this. While in showroom, just check LG model also in your budget.
Sorry, I don't have deep insight on the current lineups so I can only help this way to decide which TV to buy. You need to finalize after checking online technical and user reviews and get a demo in TV showrooms.